A simple design method of dust explosion venting size at elevated static activation pressure

To develop the application of explosion venting technology in high-pressure vessels, a new model for the design of dust explosion venting size was presented, which took the physicochemical phenomenon deriving from the elevation of the static activation pressure into account. Firstly, for confined pressure rise, the wall quenching effect originating from the dust flame thickness was considered by adopting the three-zone model. Secondly, for the venting pressure rise, the energy loss due to the discharge of high-energy burnt mixture (quantified as the specific surface area loss of the flame) was taken into account and the induced turbulence factor was introduced. Thirdly, for the venting pressure drop, a dynamic pressure relief capability evaluation model which takes into account the flame morphology evolution (tear-shaped flame) and the proportion of discharged mixture (relative volume ratio) at elevated activation pressure was proposed. The predicted maximum reduced pressure and venting size were checked against the PMMA explosion experiments and a more great performance was obtained compared with standards.     

活化剩余污泥对Pb2+的吸附热力学研究

以城市污水处理厂脱水干污泥为原料,以浓硫酸为活化剂,制备活化剩余污泥吸附剂,采用正交试验法考察了Pb2+初始质量浓度、初始pH值、吸附温度、活化剩余污泥投加量对活化剩余污泥吸附性能的影响.结果表明,活化剩余污泥对Pb2+的最佳吸附条件为pb2+初始质量浓度60 mg/L、初始pH值5、活化剩余污泥投加量100mg、吸附温度288 K,影响从高到低的各因素为Pb2+初始质量浓度、吸附温度、初始pH值、活化剩余污泥投加量.采用Langmuir、Freundlich、D-K-R吸附等温方程对不同温度下的吸附平衡试验数据进行拟合.Langmuir吸附等温方程可以较好地描述活化剩余污泥对pb2+的吸附平衡过程.其吸附过程吉布斯自由能△G为-3.35 ～-0.32 kJ/mol,焓变△H和熵变△S均为负值,表明活化剩余污泥对pb2+的吸附是自发的、以物理吸附为主的放热反应.     

红色旅游资源开发中敬畏感与自豪感对游客文明旅游行为意向的驱动机制

在我国大力推进文明旅游示范区和示范单位建设的时代背景下,引导和培育红色旅游景区游客的文明旅游行为,对于推动新时期发扬红色传统、传承红色基因和实现红色旅游资源的可持续开发具有重要的意义。基于规范激活理论、敬畏原型理论和社会认同理论,统筹考虑红色精神弘扬和红色文化传承功能,构建纳入敬畏感和自豪感情感因素的游客文明旅游行为意向的理论分析框架,选择我国红色旅游代表性景区台儿庄古城、岳麓山、陆军讲武堂旧址等作为案例调研地,运用结构方程模型和层级回归模型,实证检验在红色旅游资源开发中促进游客实施文明旅游行为的关键因素、作用机制及其驱动路径。研究发现：（1）在红色旅游资源开发情景中,后果意识、责任归属、道德规范与游客文明旅游行为意向之间的假设关系得到了验证。（2）敬畏感通过道德规范显著正向影响游客实施文明旅游行为,游客体验到的敬畏感越多,则感受到实施文明旅游行为的道德责任越多,且实施文明旅游行为的可能性越大。自豪感对道德规范和文明旅游行为意向没有显著正向影响,游客在红色旅游景区体验到的自豪感未能在促进游客文明道德责任提升和实施文明旅游行为中发挥作用。（3）景区知名度负向调节道德规范与文明旅游行为意向的正向关系,景区知名度较高时,道德规范对文明旅游行为意向的正向影响较小。因此,应增强游客对不文明行为的消极后果认知,提升游客负责任意识和道德责任,营造红色旅游的庄严氛围,激发游客的敬畏感,高度重视知名红色旅游景区的文明示范和引领,以期为我国红色旅游资源的可持续开发提供决策参考。     

活性炭材料的活化与改性

活性炭是一种应用广泛的吸附催化剂 ,其性能取决于它的孔隙结构和表面化学性质。根据活性炭的表面特性对不同物质的吸附性能 ,对活性炭进行活化和改性处理 ,能进一步满足各种特殊用途的要求。本文概述了活性炭的各种活化和改性处理技术     

Alkali activation processes for incinerator residues management

Incinerator bottom ash (BA) is produced in large amount worldwide and in Italy, where 5.1 millions tons of municipal solid residues have been incinerated in 2010, corresponding to 1.2–1.5 millions tons of produced bottom ash. This residue has been used in the present study for producing dense geopolymers containing high percentage (50–70 wt%) of ash. The amount of potentially reactive aluminosilicate fraction in the ash has been determined by means of test in NaOH. The final properties of geopolymers prepared with or without taking into account this reactive fraction have been compared. The results showed that due to the presence of both amorphous and crystalline fractions with a different degree of reactivity, the incinerator BA geopolymers exhibit significant differences in terms of Si/Al ratio and microstructure when reactive fraction is considered.     

No person is an island: The effects of group characteristics on individual trait expression

Although most researchers now espouse a person‐by‐situation interactionist approach, there remains much work to be carried out to fully understand how different features of the environment interact with personality to influence behavior. Thus, this study sought to examine the moderating effects of three group‐level constructs on the relationships between two personality traits (conscientiousness and extraversion) and individual performance and counterproductive behaviors. Specifically, using trait activation theory as an organizing framework, we considered the moderating effects of the following: (i) a previously unexamined construct called core group evaluations (CGEs); (ii) group conscientiousness composition; and (iii) group extraversion composition. Data were obtained from a sample of university football players (N = 225–252 from 40 groups). The results indicated that CGEs moderated the relationships between individual conscientiousness and both performance (subjective) and counterproductive behaviors. Group conscientiousness composition also moderated the relationships between individual conscientiousness and both performance (objective and subjective) and counterproductive behaviors. Lastly, group extraversion composition moderated the relationship between individual extraversion and counterproductive behaviors. These findings highlight the importance of considering a team's CGEs, as well as the personality composition of team members when investigating the effects of conscientiousness and extraversion on individual performance and counterproductive behaviors. Copyright © 2011 John Wiley & Sons, Ltd.     

Effects of herbicide stress on wheat cultivars from organic and conventional cropping systems

Abstract

Wheat (Triticum aestivum L.) seedlings grown from seeds produced in “organic”; (non‐chemical) and “conventional”; cropping systems are characterized by a) similar rates of root and shoot growth, b) equal sensitivity to phytotoxicity by the herbicide glyphosate, and c) equivalent basal activity of the enzyme glutathione S‐transferase (both in the roots and in the shoots). In addition, treatment of these seedlings with glyphosate leads to significantly higher contents of this enzyme both in the shoots and in the roots. However, time‐course and dose‐response investigations indicate significant differences in the induction pattern of glutathione S‐transferase: the response of “conventional”; wheat seedlings takes place earlier and with higher efficiency, than that of the “organic”; ones.     

基于地下水中四环素去除的缓释剂构建及其性能

为了有效去除地下水中抗生素等有机污染物,本文首次提出有序介孔氧化锰（O-MnO_x）为活性催化剂和过硫酸钠（Na₂S₂O₈）为氧化剂制备活化过硫酸钠缓释剂,并将其用于地下水中四环素的降解修复过程.通过有序O-MnO_x与H₂O₂和Na₂S₂O₈构建的两种类芬顿催化反应体系,明确了O-MnO_x对过硫酸钠的活化及其对水中四环素优异的降解性能.以O-MnO_x与Na₂S₂O₈为活性组分制备的缓释剂在地下水中可以缓慢释放过硫酸根离子.缓释剂中O-MnO_x加入比例增加,其释放性能减弱,而Na₂S₂O₈加入比例减少,过硫酸根释放速率就会加快.O-MnO_x可以活化过硫酸根溶...     

Engineered FeVO4/CeO2 nanocomposite as a two-way superior electro-Fenton catalyst for model and real wastewater treatment

FeVO₄/CeO₂ was applied in the electro-Fenton (EF) degradation of Methyl Orange (MO) as a model of wastewater pollution. The results of the characterization techniques indicate that FeVO₄ with triclinic structure and face-centered cubic fluorite CeO₂ maintained their structures during the nanocomposite synthesis. The effect of applied current intensity, initial pollutant concentration, initial pH, and catalyst weight was investigated. The MO removal reached 96.31% and chemical oxygen demand (COD) removal 70% for 60 min of the reaction. The presence of CeO₂ in the nanocomposite plays a key role in H₂O₂ electro-generation as a significant factor in the electro-Fenton (EF) system. The metal leaching from FeVO₄/CeO₂ was negligible (cerium 4.1%, iron 4.3%, and vanadium 1.7%), which indicates that the active species in the nanocomposite are strongly interacting with each other and are stable. The performance of the nanocatalyst in real wastewaters, salty, and binary systems was acceptable and the pollutions were removed efficiently. The synergistic effect between V, Fe, and Ce could be account as the reason for the respectable function of FeVO₄/CeO₂. The electron transfer proceeds via Haber-Weiss mechanism. A degradation pathway was proposed through by-products analysis using gas chromatography-mass spectrometry (GC–MS) technique. The pseudo-first-order kinetic model described the obtained experimental results (R² = 0.9906). The electro-Fenton system efficiency was improved by adding persulfate. The nanocomposite preserved almost its efficiency after six cycles. The obtained results demonstrate that the synergistic catalyst (FeVO₄/CeO₂) has the capability to introduce as a promising replacement of conventional catalysts in the electro-Fenton processes with brilliant proficiency.